Fluid resistor



Nov. 5, 1963 L. LEE u, ETAL FLUID RESISTOR Filed June 7, 1962 FIG.

III/(4 INVENTOR.

LEIGHTON LEE II WM?- WWW a! 3 ATTQRNEYS 7 United States Patent 3,109,459 FLUID RESISTOR Leighton Lee H, Guilford, Conn., assignor to The Lee Company, Westbrook, Conn., a corporation of Connecticut Filed June 7, 1962, Ser. No. 200,692 4 Claims. (Cl. 138--40) This invention relates to a new and improved means for providing a predetermined fluid resistance and integral filtering means incorporated in a simple assembly which may be readily inserted into a bore or similar fluid passage.

In the hydraulic and pneumatic arts, separate fixed fluid resistance elements, such as orifices, are quite often used. Such elements are commonly inserted in bores in castings, and other metal parts, in tubing, or any fluid passage to provide a fixed resistance to fluid flow. Such fluid resistance elements should desirably be easily and inexpensively insertable into a fluid passage and must seal the fluid passage to all flow, other than through the orifice of the element. One common fixed fluid resistor includes an orifice in a screw threaded member which must be screwed into a tapped bore or fluid passage and separate seals of rubber or other organic material must be provided. The tapping of the fluid passage is a relatively expensive operation and organic seals are subject to the fluid being handled and quite often give way after a period of use. Accordingly, it is an object of this invention to provide a fixed fluid resistor which may be readily installed in an untapped bore or fluid passage while providing a hermetic seal across the unit without using organic seals.

Since it is desirable to be able to remove a fixed fluid resistor element from a fluid passage to change to another resistor element or for other reasons, it is another object of this invention to provide a fixed resistor which may be easily removed from its sealing position within a fluid passage without damaging the fluid resistor element or passage in any way.

In handling liquids and gases and restricting the flow thereof by fluid resistor sometimes filterable particles carried by these fluids clog or otherwise decrease the efliciency of the fluid resistor. It is an additional object of this invention to provide in one unit for both restricting and filtering the flow of a liquid or gas.

It is a further object of this invention to provide a fixed fluid resistor element which itself is accurately machined and pre-calibrated, and may be installed in cramped quarters, between other components or in any standard corresponding size tubing or fluid passage.

It is another object of this invention to provide a filtered fixed fluid resistor which is simple in construction and manufacture, and which will be inexpensive and foolproof in installation.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangementof parts which will be exemplified in the construction hereafter set forth and the scope of the application which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a side elevation view of the fixed fluid resistor of this invention from the outside thereof;

FIG. 2 is a sectional side elevation view showing the fixed fluid resistor of FIG. 1 longitudinally sectioned; and

FIG. 3 is a sectional elevation view of the fixed fluid resistor inserted into a fluid passage of a machine part and illustrating the fluid resistor in use as assembled.

With reference to the drawings, the fixed fluid resistor includes a body 12 and a separate expander pin 14.

The body 12 is hollow and includes a cylindrical outer surface 16 provided with separate spaced annular grooves 18, 19 and 20. The portion of the cylindrical body 16 between these annular grooves constitutes lands 22 and 23.

The body 12 further includes, adjacent its end to be first inserted into a fluid passage, a chamfered shoulder 24 and a reduced diameter portion 25 with an extending inturned flange 26.

Within the cylindrical body 12, there is a precision drilled precalibrated orifice 28, see FIGS. 2 and 3. The orifice is drilled in a thickened portion 27 of the hollow body 12below the reduced cylindrical diameter 25. Leading into the precision calibrated orifice 28 are two tapered lead-in passages 30 and 31. These lead-in passages are predrilled with an included angle of 67 and to a controlled depth so that when the orifice 28 is drilled to any diameter, a constant L/ D (length/diameter) ratio for any different orifice size is obtained and standard entrance conditions for any size orifice are provided.

On one side of the orifice 28 and lead-in passage 30,

there is a flat end wall 32. On the other :side of lead-in passage 31, there is a tapered end wall 33. Adjacent end wall 33 the hollow body 12 includes a cylindrical bore 34 with a shoulder or collar 35.

Above the collar 35 there is a tapered bore 37 extending axially inside the cylindrical body 12 in the same portion that the annular grooves 18, 19 and 20 are provided. At the outer end of the inside of the body 12 there are extraction threads 36. If there is not sufiicient room on the inside of body 12 for full extraction threads 36 a partial extraction thread as shown will be more than enough for extraction requirements.

For filtering fluid passing through the fixed resistor orifice 28 in either direction a pair of filter elements 40 and 44 are provided. Filter element 40 is a screen which may be formed from a disc of perforated sheet stainless steel in such a manner to prevent distortion of the holes in the screen. Because the screen 40 is generally conical shaped with ribs thereon as shown, it has good rigidity and strength and at the same time, has a filtering area five times greater than that which could be obtained with a flat disc. The filter screen 40 is attached to an annular disc 38 having a diameter at least as large as the entrance to lead-in passage 30. The filter screen 40 and disc 38 are secured to the cylindrical body 12 by the inturned flange 26. The other filter element 44 is identical to filter element 40 and is mounted on an annular disc 42. As shown in FIG. 2 and FIG. 3, the filtering element 44 attached to disc 42 is situated against shoulder 35 on the inside of the body 12. The annular discs 38 and 42 have openings 41 and 43 respectively which are larger in diameter than the opening of lead-in passages 30 and 31.

The expander pin 14 includes a bore 46 of a diameter at least as great as the entrance to the lead-in passages 30 and 31, and further includes a threaded outer portion of the bore 48 for accommodating extraction threads. A portion of the outer surface of expander pin 50 is conically tapered in a predetermined degree and amount, relative to the tapered bore 37 of the body 12. The amount of taper is chosen such that when outer end 49 of expander pin 14, and outer end 39 of body 12 are substantially flush, a controlled radial expansion of the outside of body 12 in the area of the annular grooves 18, 19 and 20 and lands 22 and 23 has taken place. This radial expansion effectively seals the body 12 carrying the filtered fixed resistor within a bore or fluid passage. This radial expansion and sealing is generally described in my prior art 2,821,- 323, granted January 28, 1958.

FIG. 3 shows the filter fixed fluid resistance after it has been inserted into a fluid passage. The operation of insertion and removal of the element will be described in connection with FIG. 3. A casting 52 or any other metal part having a fluid passage therein, may be provided with a bore 54. For deep holes and best results, a tapered shoulders 58 is provided in the bore and an enlarged reamed hole 56 is provided at the outer portion of the fluid pasage. The hollow body 12 including a precalibrated fixed resistor 28 and filters 40 and 44 is of such outer diameter to provide a slip fit into the reamed hole 56. After slipping into the hole, the chamfered shoulder 24 of the cylindrical body 12 will mate with tapered shoulder 58 of the fluid passage. The expander pin 14 is then inserted into the outer end of the body 12 and is pressed thereinto until end 49 of pin 14 is substantially flush with end 39 of cylindrical body 12. Because of the taper 50 on pin 14 and tapered area 37 on the inside of cylindrical body 12, the pin 14 will expand the cylindrical body '12 in the area indicated at 66 to form a hermetic seal of the body 12 against the walls of reamed hole '56.

To remove the fixed fluid resistor element, an extractor bolt (not shown) having threads corresponding to threads 48 on expander pin 14 is screwed into pin 14 and a striker or other known puller may be used to remove pin 14. In a similar manner, another set of extraction threads on an extraction member (not shown) corresponding to threads 36 on member 12, may be screwed into the hollow body 12 and it may be pulled out by conventional means.

Because the orifices 28 are pre-calibrated and are precision drilled, they provide a definite and known fixed resistance to fluid flow. In order that a user of these fixed fluid resistor elements may choose a proper value for the orifice and fixed fluid resistance, indicia 60 and 62 representing the value of the fixed fluid resistance of orifice 28 may be placed on inturned flange 26 or in any other suitable position. As one example of indicia, the angle between markings '60 and 62 could bear a proportional relationship to the value of the fixed fluid resistance. As a further example, the indicia markings 64 might be placed on end 39 of body 12 to indicate the degree of flow tolerance in either forward or reverse direction through the precalibrated orifice 28.

Based on evaluation tests, the controlled expansion of the cylindrical body 12 sealed the fixed fluid resistor so effective that it could withstand a pressure drop of 12,000 p.s.i. without having the body 12 move and yet the pin 14 and body '12 could be extracted without any damage to the bore 56 in the casting 52.

-As an example of a typical size fixed fluid resistor constructed in accordance with this invention, the body 12 could have outside diameter of 0.187 inch to allow it to be installed in any A inch A.'N. tubing fitting. The overall length from surface 39 of body -12 to the tip of filter screen 40 would be 0.55 inch. The orifice could by any one of a series of predetermined diameters provide a known resistance to fluid flow and the L/D ratio of the orifice would be 1.5 for all orifice sizes. For the required expansion surface 39 of body 12 and surface 49 of pin 14 are flush to a tolerance of 1.005 inch. The foregoing dimensions and tolerances are, of course, by way example only.

From the foregoing it can be seen that there is provided novel pre-calibrated fluid resistor with integral filters for filtering flow in either direction which is easy to install at very low installation cost in a simple and foolproof procedure. A single package both restricts flow and filters fluid, and no organic seals are needed. It is further evident that the device may be readily removed without damage and can be inserted in any corresponding size fluid passage, whether in cramped quarters or in a standard size tube.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent Without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. An insertable and removable fluid resistor for use in restricting flow in a fluid passage of a metal part comp (a) a hollow body having a generally cylindrical outer surface,

(b) a plurality of separate spaced apart annular grooves in a portion of the cylindrical outer surface,

(0) a pre-calibrated fluid restricting orifice within the hollow body,

(d) a tapered inner bore within the hollow body extending throughout the portion of the body having the annular grooves,

(e) a separate hollow expander pin adapted to radially expand the outside of the hollow body, and

(f) a tapered outer surface on the hollow metal expander pin for oooperating with the tapered inner bore when the expander pin is moved axially therein to thereby uniformly and radially expand the metal body into fluid type sealing engagement with the cylindrical bore.

2. A removable fluid resistor for insertion into a cylindrical bore of a metal part, including a tubular fluid passage, the resistor comprising;

(a) a hollow metal body having a generally cylindrical outer surface of a diameter for a slip fit into the cylindrical bore of the metal part,

(b) a plurality of separate spaced apart annular grooves in a portion of the cylindrical outer surface of the body,

(c) a pro-calibrated fluid restricting orifice within the metal body adjacent an end thereof,

(d) a tapered inner bore portion on the inside of the hollow body at a position spaced from the orifice and extending throughout the portion of the body having annular grooves on the outside,

(e) extraction threads on the inside of the cylindrical body adjacent an outer end of the body,

(f) a pair of screen filters secured within the body,

one on each side of the orifice,

(g) a hollow metal expander pin adapted to radially expand the hollow body, the inside diameter of the expander pin being larger than the orifice,

(h) a tapered outer surface on the metal expander pin for mating with the tapered inner bore .when the expander pin is moved axially therein, until the outer end of the expander pin is substantially flush with the outer end of the hollow metal body to uniformly and radially expand the plug into fluid tight sealling engagement with the bore of the metal part, an

(i) extraction threads on the inside of the hollow metal expander pin.

3. A removable fluid resistor for easy insertion into a cylindrical bore and fluid passage of a metal part, the cylindrical bore including a tapered shoulder, the fluid resistor comprising;

( a) a hollow metal body having a generally cylindrical outer surface of a diameter for slip fit into the cylindrical bore,

(11) a plurality of separate spaced apart annular grooves in a portion of the cylindrical surface,

(0) a chamfered shoulder on the outer surface of the cylindrical body for mating with the tapered shoulder in the bore of the metal part,

(d) a pre calibrated fluid restricting orifice within the metal body adjacent an end thereof,

( e) a pair of frustoeonical lead-in passages formed in the bore of the hollow metal body and leading into the orifice from both sides thereof,

(f) a tapered inner portion in the bore of the hollow body extending throughout that portion of the body having annular grooves on the outside thereof,

(g) extraction threads on the inside of the hollow metal body adjacent the outer end thereof,

(It) a pair of generally conical perforated screen filters secured within the bore of the body, one on each side of the orifice and lead-in passages,

(i) a separate hollow metal expander pin having an inside diameter larger than the lead-in passages to the orifice,

(j) a tapered outer surface on the metal expander pin cooperating with the tapered inner bore when the expander pin is moved axially thereinto until the outer end of the expander pin is substantially flush with the outer end of the metal body to thereby uniformly and radially expand the body into fluid tight sealing engagement with the bore of the metal part, and

(k) extraction threads on the inside of the expander pin.

4. A removable fluid resistor for insertion into a cylindrical bore of a metal part, the cylindrical bore including a tapered shoulder, the fixed resistor comprising:

(a) a hollow metal body having a portion of the outer surface of cylindrical shape and of a diameter for slip fit into the cylindrical bore,

(b) a plurality of separate spaced apart annular grooves in a portion of the cylindrical outer surface of the metal body.

() a chamfered shoulder on the outer surface of the cylindrical body for mating with the tapered shoulder in the bore of the metal part,

(d) an extending inturned flange on an inner end of the metal body,

(e) a pro-calibrated fluid resisting orifice within the hollow metal body adjacent an end thereof,

(1) a pair of frustoconical lead-in passages formed in the bore of the hollow metal body and leading into the orifice from both sides thereof, the frustoconical lead-in passages having an included angle of 67 so that any size orifice has a constant length to diameter ratio,

(g) a tapered portion in the bore of the hollow metal body positioned outwardly of the orifice and terminating above the orifice with a shoulder in the hollow metal body,

(11) extraction threads on the inside of the hollow metal body adjacent the outer end thereof,

(i) a pair of screen filters formed of perforated sheet metal secured to an annular disc, the screens being of generally conical shape and one being positioned on one side of the orifice and held by the inturned flange, while the other screen of identical size is positioned on the other side of the orifice at the shoulder portion of the hollow body,

(j) a separate hollow metal expander pin having an inside diameter larger than the diameter of the en trance to the lead-in orifice passages,

(k) a tapered outer surface on the metal expander pin for cooperating with the tapered inner bore when the expander pin is pressed axially thereinto, until the outer end of the expander pin is substantially flush with the outer end of the metal part, thereby uniformly and radially expanding the metal body into fluid tight sealing engagement with the bore of the metal part, and

(l) extraction threads on the inside of the hollow metal expander pin.

References Cited in the file of this patent UNITED STATES PATENTS 1,953,110 Holtone Apr. 3, 1934 2,020,412 Handler Nov. 12, 1935 2,790,463 Delano et a1. Apr. 30, 1957 2,821,323 Lee Jan. 28, 1958 2,992,659 Thomas July 18, 1961 3,067,777 Briscoe Dec. 11, 1962 

1. AN INSERTABLE AND REMOVABLE FLUID RESISTOR FOR USE IN RESTRICTING FLOW IN A FLUID PASSAGE OF A METAL PART COMPRISING; (A) A HOLLOW BODY HAVING A GENERALLY CYLINDRICAL OUTER SURFACE, (B) A PLURALITY OF SEPARATE SPACED APART ANNULAR GROOVES IN A PORTION OF THE CYLINDRICAL OUTER SURFACE, (C) A PRE-CALIBRATED FLUID RESTRICTING ORIFICE WITHIN THE HOLLOW BODY, (D) A TAPERED INNER BORE WITHIN THE HOLLOW BODY EXTENDING THROUGHOUT THE PORTION OF THE BODY HAVING THE ANNULAR GROOVES, (E) A SEPARATE HOLLOW EXPANDER PIN ADAPTED TO RADIALLY EXPAND THE OUTSIDE OF THE HOLLOW BODY, AND (F) A TAPERED OUTER SURFACE ON THE HOLLOW METAL EXPANDER PIN FOR COOPERATING WITH THE TAPERED INNER BORE WHEN THE EXPANDER PIN IS MOVED AXIALLY THEREIN TO THEREBY UNIFORMLY AND RADIALLY EXPAND THE METAL BODY INTO FLUID TYPE SEALING ENGAGEMENT WITH THE CYLINDRICAL BORE. 